Hey there!
My mother had struggled with her weight her entire life. Ranging from being super skinny and healthy to being very overweight and disgusted with herself. I have witnessed her go on and off many diets and exercise routines, lose weight and gain it back. In her adult life she has never succeeded in losing weight and keeping it off. I know the same is true for hundreds of thousands of people in the world.

Last year I managed to lose 50lbs through hard work, eating right and sticking to a plan. She always made silly comments about how I am "crazy" or "to dedicated" but I chalked it up to being jealous. She started really getting on my case when I hit 130, telling me I was to skinny and needed to regain some weight. I attempted to explain to her that at 130 and 5'5 I was totally within a healthy weight range. My mom started asking me for tips to lose weight but whatever tips I would tell her she would completely dismiss because "I didn't know what I was talking about". For example her breakfast is a milk shake, made with full fat ice cream, some meal replacement and maybe fruit. I told her she should switch the ice cream out with Greek yogurt or some milk and ice because that would give her better nutrition. She told me no because the ice cream has the calcium she needs and that a calorie is a calorie no matter what. When I attempted to explain that sure calories are calories but it does make a difference if its a calorie from bad fat or good fat she laughed telling me I was insane?! What?! I'm not the one eating ice cream for breakfast lady, sheeesh.

However she is not the only person to do this. My old boss at work used to do the same thing, ask me for advice and then dismiss what I have to say. My fiances parents do it to him to saying that he "couldn't possibly know what he is talking about". It has happened several other times as well but I am sure you get the idea now so I will quit my rambling.
Does anyone else experience this?

Yes lol. I love it when people ask you "how you did it" and then completely act like you have no idea what you are talking about! My neighbor does this.. well she does this for everything, so I am not suprised.
My mom is also over weight.. the other day I was happy to see that their scale had 1/2 pound marks along with the pound markers. I weighed less.. I was telling her this and the first thing out of her mouth was "oh so you haven't lost as much as you thought!" Actually, I lost more. Thanks mom

I get this with my parents too. My dad REFUSES to eat most vegetables and he hates fish. In fact, his diet consists mostly of cheese, sausages and meat. He goes to the gym for an hour and a half every night. Last time I saw him I saw him I told him he needs to fix his diet and incorporate healthy fats (like nuts and legumes) and more veggies and that he should cut his cheese consumption WAY down. I told him the "diet is for weight loss, exercise is for fitness" mantra and he scoffed it all off.

He told me nuts are too fatty, legumes are gross and that cheese has calcium which he needs for bone health since he's working out all the time.

What -REALLY- bothers me is that he's a controlling person who won't only make poor choices for himself, but for my mother, his wife, too. He won't let her cook fish in the house because he doesn't like the smell. He won't let her buy veggies because he thinks they're a waste of money. She's morbidly obese and gets sick every time she goes somewhere because her immune system is shot and I feel bad for her. There's some control issues there too and he won't let her get a driver's license or leave the house without him. At least when I lived with them (he didn't want to let me leave either, I had to basically plan my entire move behind his back so he wouldn't sabotage it) I took her to fish places or for salads or wraps and out places and she got sick less often and got some movement in her (like a walk around the mall). Now she's just getting worse and worse because of his control.

When I tell her she should become independent or demand fish/veggies/healthier stuff she says "oh, your father's joy is his food and he works so hard, he should be able to eat what he wants in his own home and not have to deal with things grossing him out"

Sorry, this went off topic, but the rant pretty much wrote itself once I got started.

Yes, people not taking advice or giving you credit for your efforts really sucks.

It's not because you're young, trust me. It happens to me and I'm 42. It seems difficult for people to ask about or compliment others on weight loss without some sort of advice or hints about the "right way"

I don't know why that is really. It could be jealousy, concern, or something entirely different. All you can really do is listen politely to what they say then continue to do what works for you.